Box C/D RNAs guide the site-specific formation of 2′-O-methylated nucleotides(Nm)of RNAs in eukaryotes and archaea.Although C/D RNAs have been profiled in several archaea,their targets have not been experimentally de...Box C/D RNAs guide the site-specific formation of 2′-O-methylated nucleotides(Nm)of RNAs in eukaryotes and archaea.Although C/D RNAs have been profiled in several archaea,their targets have not been experimentally determined.Here,we mapped Nm in r RNAs,t RNAs,and abundant small RNAs(s RNAs)and profiled C/D RNAs in the crenarchaeon Sulfolobus islandicus.The targets of C/D RNAs were assigned by analysis of base-pairing interactions,in vitro modification assays,and gene deletion experiments,revealing a complicated landscape of C/D RNA-target interactions.C/D RNAs widely use dual antisense elements to target adjacent sites in r RNAs,enhancing modification at weakly bound sites.Two consecutive sites can be guided with the same antisense element upstream of box D or D′,a phenomenon known as doublespecificity that is exclusive to internal box D′in eukaryotic C/D RNAs.Several C/D RNAs guide modification at a single non-canonical site.This study reveals the global landscape of RNA-guided 2′-O-methylation in an archaeon and unexpected targeting rules employed by C/D RNA.展开更多
Polyamines have been discovered for hundreds of years and once considered as a class of phytohormones.Polyamines play critical roles in a range of developmental processes.However,the molecular mechanisms of polyamine ...Polyamines have been discovered for hundreds of years and once considered as a class of phytohormones.Polyamines play critical roles in a range of developmental processes.However,the molecular mechanisms of polyamine signaling pathways remain poorly understood.Here,we measured the contents of main types of polyamines,and found that endogenous level of thermospermine(T-Spm)in Arabidopsis thaliana is comparable to those of classic phytohormones and is significantly lower than those of putrescine(Put),spermidine(Spd),and spermine(Spm).We further found a nodule-like structure around the junction area connecting the shoot and root of the T-Spm biosynthetic mutant acl5 and obtained more than 50 suppressors of acl5 nodule structure(san)through suppressor screening.An in-depth study of two san suppressors revealed that NAP57 and NOP56,core components of box H/ACA and C/D snoRNPs,were essential for T-Spm-mediated nodule-like structure formation and plant height.Furthermore,analyses of rRNA modifications showed that the overall levels of pseudouridylation and 2′-O-methylation were compromised in san1 and san2 respectively.Taken together,these results establish a strong genetic relationship between rRNA modification and T-Spm-mediated growth and development,which was previously undiscovered in all organisms.展开更多
RNA molecules serve a wide range of functions that are closely linked to their structures.The basic structural units of RNA consist of single-and double-stranded regions.In order to carry out advanced functions such a...RNA molecules serve a wide range of functions that are closely linked to their structures.The basic structural units of RNA consist of single-and double-stranded regions.In order to carry out advanced functions such as catalysis and ligand binding,certain types of RNAs can adopt higher-order structures.The analysis of RNA structures has progressed alongside advancements in structural biology techniques,but it comes with its own set of challenges and corresponding solutions.In this review,we will discuss recent advances in RNA structure analysis techniques,including structural probing methods,X-ray crystallography,nuclear magnetic resonance,cryo-electron microscopy,and small-angle X-ray scattering.Often,a combination of multiple techniques is employed for the integrated analysis of RNA structures.We also survey important RNA structures that have been recently determined using various techniques.展开更多
Assembly of eukaryotic ribosome is a complicated and dynamic process that involves a series of intermediates.It is unknown how the highly intertwined structure of 60S large ribosomal subunits is established.Here,we re...Assembly of eukaryotic ribosome is a complicated and dynamic process that involves a series of intermediates.It is unknown how the highly intertwined structure of 60S large ribosomal subunits is established.Here,we report the structure of an early nucleolar pre-60S ribosome determined by cryo-electron microscopy at 3.7 A resolution,revealing a half-assembled subunit.DomainsⅠ,ⅡandⅣof 25S/5.8S rRNA pack tightly into a native-like substructure,but domains Ⅲ,ⅣandⅤare not assembled.The structure contains 12 assembly factors and 19 ribosomal proteins,many of which are required for early processing of large subunit rRNA.The Brx1-Ebp2 complex would interfere with the assembly of domains Ⅳ and Ⅴ.Rpf1,Mak16,Nsa1 and Rrp1 form a cluster that consolidates the joining of domainsⅠandⅡ.Our structure reveals a key intermediate on the path to establishing the global architecture of 60S subunits.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB0570000,XDB37010201)the Basic Research Program Based on Major Scientific Infrastructures of Chinese Academy of Sciences(JZHKYPT-2021-05)+1 种基金the National Natural Science Foundation of China(91940302,91540201,31430024,31325007)the National Key Research and Development Program of China(2017YFA0504600)。
文摘Box C/D RNAs guide the site-specific formation of 2′-O-methylated nucleotides(Nm)of RNAs in eukaryotes and archaea.Although C/D RNAs have been profiled in several archaea,their targets have not been experimentally determined.Here,we mapped Nm in r RNAs,t RNAs,and abundant small RNAs(s RNAs)and profiled C/D RNAs in the crenarchaeon Sulfolobus islandicus.The targets of C/D RNAs were assigned by analysis of base-pairing interactions,in vitro modification assays,and gene deletion experiments,revealing a complicated landscape of C/D RNA-target interactions.C/D RNAs widely use dual antisense elements to target adjacent sites in r RNAs,enhancing modification at weakly bound sites.Two consecutive sites can be guided with the same antisense element upstream of box D or D′,a phenomenon known as doublespecificity that is exclusive to internal box D′in eukaryotic C/D RNAs.Several C/D RNAs guide modification at a single non-canonical site.This study reveals the global landscape of RNA-guided 2′-O-methylation in an archaeon and unexpected targeting rules employed by C/D RNA.
基金supported by the National Natural Science Foundation of China(31788103,32122012,32100221,91940302,31430024)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA24040202)+1 种基金the Chinese Academy of Sciences Youth Innovation Promotion Association(2019099)the CAS Key Technology Talent Program(2017)。
文摘Polyamines have been discovered for hundreds of years and once considered as a class of phytohormones.Polyamines play critical roles in a range of developmental processes.However,the molecular mechanisms of polyamine signaling pathways remain poorly understood.Here,we measured the contents of main types of polyamines,and found that endogenous level of thermospermine(T-Spm)in Arabidopsis thaliana is comparable to those of classic phytohormones and is significantly lower than those of putrescine(Put),spermidine(Spd),and spermine(Spm).We further found a nodule-like structure around the junction area connecting the shoot and root of the T-Spm biosynthetic mutant acl5 and obtained more than 50 suppressors of acl5 nodule structure(san)through suppressor screening.An in-depth study of two san suppressors revealed that NAP57 and NOP56,core components of box H/ACA and C/D snoRNPs,were essential for T-Spm-mediated nodule-like structure formation and plant height.Furthermore,analyses of rRNA modifications showed that the overall levels of pseudouridylation and 2′-O-methylation were compromised in san1 and san2 respectively.Taken together,these results establish a strong genetic relationship between rRNA modification and T-Spm-mediated growth and development,which was previously undiscovered in all organisms.
基金National Key R&D Program of China(2021YFA1301500,2017YFA0504600,2022YFC2303700,2022YFA1302700,2022YFF1203100)National Natural Science Foundation of China(U1832215,32171191,91940302,32230018 and 32125007)+6 种基金Strategic Priority Research Program of Chinese Academy of Sciences(XDB37010201,XDB0490000)Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYPY20220019)the Fundamental Research Funds for the Central Universities(WK9100000032 and WK9100000044)Guangdong Science and Technology Department(2022A1515010328,2020B1212060018 and 2020B1212030004)the Postdoctoral Foundation of Tsinghua-Peking Center for Life Sciences[to J.Z.]the Beijing Advanced Innovation Center for Structural Biology[to Q.C.Z.]the Tsinghua-Peking Joint Center for Life Sciences[to Q.C.Z.].
文摘RNA molecules serve a wide range of functions that are closely linked to their structures.The basic structural units of RNA consist of single-and double-stranded regions.In order to carry out advanced functions such as catalysis and ligand binding,certain types of RNAs can adopt higher-order structures.The analysis of RNA structures has progressed alongside advancements in structural biology techniques,but it comes with its own set of challenges and corresponding solutions.In this review,we will discuss recent advances in RNA structure analysis techniques,including structural probing methods,X-ray crystallography,nuclear magnetic resonance,cryo-electron microscopy,and small-angle X-ray scattering.Often,a combination of multiple techniques is employed for the integrated analysis of RNA structures.We also survey important RNA structures that have been recently determined using various techniques.
基金Strategic Priority Research Program of Chinese Academy of Sciences(XDB08010203)National Key R&D Program of China(2017YFA0504600)the National Natural Science Foundation of China(Grant Nos.31430024,91540201 and 31325007).
文摘Assembly of eukaryotic ribosome is a complicated and dynamic process that involves a series of intermediates.It is unknown how the highly intertwined structure of 60S large ribosomal subunits is established.Here,we report the structure of an early nucleolar pre-60S ribosome determined by cryo-electron microscopy at 3.7 A resolution,revealing a half-assembled subunit.DomainsⅠ,ⅡandⅣof 25S/5.8S rRNA pack tightly into a native-like substructure,but domains Ⅲ,ⅣandⅤare not assembled.The structure contains 12 assembly factors and 19 ribosomal proteins,many of which are required for early processing of large subunit rRNA.The Brx1-Ebp2 complex would interfere with the assembly of domains Ⅳ and Ⅴ.Rpf1,Mak16,Nsa1 and Rrp1 form a cluster that consolidates the joining of domainsⅠandⅡ.Our structure reveals a key intermediate on the path to establishing the global architecture of 60S subunits.